A steering mechanism known as an Ackerman-Jeantaud steering mechanism includes a steering link mechanism connecting together right and left vehicle wheels (an assembly including a tire, a rim, a hub, an in-wheel motor, etc.), and is hereinafter referred to as “vehicle wheel” or simply “wheel”, and used to steer the vehicle wheels. This steering mechanism includes tie rods and knuckle arms such that while the vehicle is turning, the right and left wheels move around the same center point.
Such a steering mechanism is disclosed in the below-identified Patent document 1. This steering mechanism includes steering shafts disposed between the font right and front left wheels, and between the rear right and rear left wheels, respectively, and each including right and left divided portions. A switching means is disposed between the right and left divided portions of each steering shaft, and is capable of switching the rotating direction of the steering shaft from one to the opposite direction, whereby the vehicle can move laterally with the steering angles at 90 degrees. The below-identified Patent document 2 discloses a four-wheel steering vehicle of which an actuator is actuated when the front wheels are steered such that the rear wheels are steered by the actuator.
The below-identified Patent documents 3 and 4 each discloses a structure of which each wheel includes a steering actuator (steering mechanism) so that each wheel is steerable to a predetermined angle independently of the other wheels (see numeral 70 (steering actuator) and numeral 71 (steering mechanism), in FIG. 12). Since the wheels are steerable independently of each other, special travel modes such as pivot turning are possible.